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Ask Hank F. Your Own Question
Hank F.
Hank F., Technician
Category: Small Engine
Satisfied Customers: 15277
Experience:  Certified on Onan and Generac generators
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I bought a 1995 Fleetwood Motorhome last month that came

Customer Question

JA: Hi. How can I help?
Customer: Hello, I bought a 1995 Fleetwood Motorhome last month that came with an Onan Marquis 7000 Model number 7NHMFA26106D. The generator has been difficult to start form the beginning from a weak starter to hard starts without firing and once it does fire would die as soon as I let off of the start switch either form inisde the motorhome or at the generator itself. I found that if I hold down the star switch for several seconds after it initially seems to fire is the only way that the generator will continue running. I replaced the oil pressure sensor already but that did not solve the problem.
JA: Do you have fuel in the tank? If so, is the shut-off valve open and the fuel clean?
Customer: Yes, the generator is our of the motorhome and it is getting it's fuel from a gas can.
JA: Do you plan on doing the work yourself?
Customer: I am doing the work myself.
JA: Anything else we should know to help you best?
Customer: uh, I am a computer technician by trade.
Submitted: 2 months ago.
Category: Small Engine
Expert:  Hank F. replied 2 months ago.

Hello, my name is ***** ***** I am going to assist you with this.

The first thing you need to do is to give the genset a good tune up - change the oil and oil filter, install a new air filter, and new spark plugs properly gapped to .025".

Make sure the choke is working and properly adjusted.

If this unit has been sitting for a long time, there is a good chance that the carb is bad.

Customer: replied 2 months ago.
I have already replaced the air cleaner, the rear spark plug, the front one looks ok, the oil filter and the oil. I put a new starter in it but didn't realize that a heavy duty set of jumper cables was still inadequate for the amount of amps that the starter pulls. I thought that the new starter was defective when it wouldn't turn the engine over. So, thinking that the new starter was defective I paid $100 more than I paid for the new starter from to buy a starter directly from Onan only to find that the generator could still barely turn over. That's when I decided to connect battery cables directly to the generator and found that it turns over just fine now. Once it starts it runs just fine and can easily push both of the motorhomes AC units, but when I turn it off, no matter how long it has been running for it is hard to start again. The throttle doesn't even open until I have been cranking the starter for several seconds. If I manually open the throttle it will fire sooner but it always seems to stop firing after that first "catch" and then I have to continue holding down the start button for a few more seconds of it will simply die.
Customer: replied 2 months ago.
I have no indication that the are any problems with the carburetor.
Customer: replied 2 months ago.
I ordered a new fuel filter as well but it was the wrong one. A new one is coming but I don't think the issues have anything to do with a clogged fuel filter.
Customer: replied 2 months ago.
When I hook a test light to the coil I can see that the generator stops sending power to the coil if I let off of the start button when it first starts to fire, so I know that the issue is a computer/electrical issue and not carburetor.
Expert:  Hank F. replied 2 months ago.

The reason you are losing power to the coil when you release the start button is because something is telling the genset to shut down. That's how the control board shuts the genset down - it kills power to the fuel pump and ignition system.

The hard starting is either a carb or choke issue.

The shut down may be because the genset is no producing power right away.

Connect a voltmeter to the output of the genset, and start it up. See what the voltage is doing. Does it produce 120V as it is starting up, or does it take a few seconds for voltage to build up?

Customer: replied 2 months ago.
It starts fine when I open the throttle but I think that has to do with the electronic governor waiting for conditions to run or P1-5 to GND. With a test light probe in P1-5 and the lights ground on the positive and a volt meter hooked up to L1, I find that after it initially fires there is a 2 second delay before the voltage hits 120v and the test light comes on at the same time.
Customer: replied 2 months ago.
I wouldn't have that 2 second delay though if the governor opened the throttle right away when it initially fires.
Customer: replied 2 months ago.
Even if I rev it up as it starts it wont catch for the 2 seconds. It doesn't generate voltage right away and it seemed like it didn't matter how high it revved, if it didn't run for 2 seconds before I let off of the start switch it would die, even if it did start generating voltage. It didn't feel like a good experiment to see voltages of 200 when it revved up like that.
Expert:  Hank F. replied 2 months ago.

I am going to opt out of this.

Perhaps another expert will help you.

Customer: replied 2 months ago.
Do I get my money back?